|Year : 2015 | Volume
| Issue : 3 | Page : 230-232
Burden of atrial fibrillation in India
Vijay Bohra, Gautam Sharma, Rajnish Juneja
Department of Cardiology, All India Institute of Medical Sciences, New Delhi, India
|Date of Web Publication||23-Feb-2016|
Department of Cardiology, All India Institute of Medical Sciences, New Delhi
Source of Support: None, Conflict of Interest: None
Atrial fibrillation (AF) is becoming a major public health burden worldwide, and its prevalence is set to increase owing to the increase in the elderly population. Despite the availability of good epidemiological data on the prevalence of AF in the Western countries, the corresponding data are limited from our country. In this article, we have tried to assimilate all the data available. A national registry on AF does provide some insight into the causes and effects. It is necessary to have a precise knowledge of the national burden for formulating national evidence-based policy and guidelines.
Keywords: Atrial fibrillation, rheumatic heart disease, national data
|How to cite this article:|
Bohra V, Sharma G, Juneja R. Burden of atrial fibrillation in India. J Pract Cardiovasc Sci 2015;1:230-2
| Introduction|| |
Atrial fibrillation (AF) is the most common arrhythmia and was first demonstrated on electrocardiography more than a century ago.  It has since then become increasingly recognized as a major global health burden due to the increasing life expectancy and global increase in the coronary risk factors with age. Although accurate worldwide estimates are lacking, calculations suggest that ≥1% of the adult population is affected in the developed world. , In our country, there is virtually no data on AF, most of the data that has been derived is from international studies  with an Indian cohort.
There is indeed a dearth of data on epidemiologic outcomes in patients of rheumatic AF in the country leading to inconsistent practice patterns as regards medical therapy, especially oral anticoagulation. This may expose these patients at a higher risk of thromboembolic and sometimes bleeding diathesis.
In India, rheumatic heart disease (RHD) still remains the predominant etiology of AF as documented by a small study from a rural population from the Himalayan hills (n = 137) in which 61.31% patients had AF of RHD etiology.  This study, which was done prospectively over 02 years from Apr 2006 to Mar 2008, the mean age of the patients was 51.24 ± 15.36 years much younger than the western population. This also emphasizes the huge economic implication because of the disability-adjusted life years (DALYs). Other etiologies which were a distant second to RHD were hypertension (10.2%) and chronic obstructive pulmonary disease (10.2%). AF was more common in females with female to male ratio of 1.24, consistent with a study published by Nadeem et al. in 1999. 
Similar epidemiologic observation was made from the data obtained from the Indian cohort of the REALIZE AF study  in which valvular heart disease contributed to 40.7% cases in the Indian cohort as compared to the Global average of 26.7%. The average of this cohort was 60 years, and 55% were males. Hypertension was present in 50.8% cases as compared to 72.2% of patients from the global cohort. AF was documented more often in patients with electrocardiographic or echocardiographic evidence of hypertensive heart disease. The other international registry including an Indian cohort, the RE-LY AF did not observe the same and valvular heart disease contributing to AF was not much different from the global average (21.8% vs. 25.4%).  Data from the UK-based West Birmingham AF project showed a relatively low prevalence of AF among Indo-Asian participants aged >50 years (0.6%), compared to general study population aged ≥50 years (2.4%).  AF was found to be the most common arrhythmia (66%) seen by the clinicians as shown in the PANARM HF study. 
The first Indian registry, the Indian Heart Rhythm Society (IHRS) AF study  recruited 1000 patients with AF at twenty different cities across the country; RHD still remained the most common etiology (42%). Women participants were 51% in this registry data. The registry also studied AF control at 6 months and 12 months, thromboembolic events - cardiovascular events, stroke, and international normalized ratio (INR) control. 19.5% cases had paroxysmal AF while 33.7% had permanent AF.
What this etiologic trend does is reproduced in the RE-LY-AF study where patients from Africa, India, and the Middle East were on average 10-12 years younger than those from other regions of the world. Similarly, in the REALIZE AF and IHRS AF study, the average age of patients with AF in India was 60 years and 54 years, respectively (a decade younger than Western counterparts). Thus, it increases the economic burden by more DALY's lost. The most dreaded complication of AF is stroke/thromboembolic events, the annual incidence of such an event in nonvalvular AF is 4%/year as compared to 17-18%/year in patients with rheumatic AF. Hence, demonstrating increased morbidity and mortality translating to further increase in the economic burden on the national resources.
The situation becomes grimmer when we observe that the time spent in the therapeutic range for oral anticoagulation is significantly lower in countries outside North America and Western Europe. As shown in the ROCKET AF trial among closely monitored patients in the warfarin arm, a substantial proportion of participants from different geographical regions had subtherapeutic anticoagulation (INR <2 for >25% of the time): 44% in India and 27% in Latin America. About 37% in East Asia and 35% in Eastern Europe.  The newer anticoagulants such as dabigatran and apixaban which have become anticoagulants of choice in western countries are expensive and beyond the reach of a common man.
The morbidity and mortality that can be attributed to AF have even pushed investigators to investigate rhythm control in patients of RHD with AF. In the CRRAFT trial  144 patients with chronic rheumatic AF were randomized in a double-blind protocol. Patients with sinus rhythm (SR) demonstrated a significant increase in exercise time, had improvement in functional class and quality of life score. This study shows that maintenance of SR appeared to be superior to ventricular rate control in patients with rheumatic AF in terms of an effect on morbidity and mortality.
In a prospective randomized study  aimed at evaluating efficacy of early direct current cardioversion (DCCV) following successful Percutaneous balloon-mitral-valvotomy (PBMV) in patients with long-standing AF, patients of rheumatic mitral stenosis (MS) with AF who underwent successful PBMV were either DC cardioverted and administered oral amiodarone for 6 weeks or continued on conventional therapy without cardioversion. At a mean follow-up of 7.6 months, 95% in the group that was not cardioverted continued to be in AF. In the second group, 87% patients were in SR, and 13% had reverted to AF. There was a significant improvement in quality of life (SF 36 score) in group 2 (P = 0.001), with no deaths, stroke, or adverse drug effects in either group. The authors postulated that in patients with rheumatic MS and AF, early DCCV and a short duration oral amiodarone following successful PBMV may be a reasonable strategy to short or medium term SR. This strategy also saved on hospital and patient costs by allowing early discharge and not readmitting for DCCV.
The burden of rheumatic AF in India makes it an important health issue. As mentioned, lack of a robust national epidemiological data and incomplete understanding of the pathology makes the problem more challenging. Indeed, there are very few studies comparing the pathology of the remodeled substrate in patients of RHD with AF and SR. Recently, a study looked at the pathology of excised left atrial appendages in patients with RHD undergoing mitral valve replacement. The histopathological findings of the atrial myocardium were characterized by significantly more cardiomyocyte hypertrophy, nuclear enlargement, perinuclear clearing, sarcoplasmic vacuolation, fibrosis, and inflammation in the patients with AF. Electron microscopy revealed cardiomyocytes with depletion of the contractile elements (Z-bands), glycogen particle accumulation, and an increase in mitochondria. Cells severely affected by AF showed loss of contractile elements with extensive areas of sarcoplasmic vacuolation, presence of myelin figures, and mitochondrial aggregates. In summary, the left atrial substrate in AF as compared with SR, in RHD patients, is associated with significant degenerative remodeling and ongoing inflammation that is associated with extensive fibrosis. 
Surgery for AF in India is utilized for patients with rheumatic AF undergoing valve surgery. Maze procedure and it's modifications have been very promising in this regard. The radiofrequency bipolar maze procedure has shown excellent results with 80% freedom from AF at 5 months and enhancing the transport function of the atrium as before. 
Catheter ablation for AF is an accepted modality, especially in case of nonvalvular AF. In India, there are only a few centers that are performing this procedure as a part of a regular structured program. In the last 5 years, 76 patients have undergone ablation procedure for AF at the All India Institute of Medical Sciences, New Delhi. Of these patients, four had RHD with mild MS, one patient had hypertrophic obstructive cardiomyopathy, and four had long-standing persistent AF. The rest of the patient had paroxysmal AF with no underlying structural heart disease. There was an overall 16% documented recurrence rate at 1 year for single procedure. There was no procedural complication. One patient died 6 months after the procedure because of anticoagulant-related cerebral hemorrhage. In our limited experience in rheumatic AF, the patients remained in SR at 1 year, but a randomized trial is required to address the question in an appropriate manner.
| Conclusion|| |
The logical future direction at this stage is to conduct longitudinal epidemiological studies to have a proper estimate of the burden of AF in India. It is equally important to educate and increase awareness among both the caregivers and the recipient patients. Simultaneous improvement in management including preferring rhythm control where possible and improving availability of point-of-care measurements of INR. Evaluations of the overall public-health burden of AF with emphasis on rheumatic AF and the formulation of a national consensus policy are a much-desired need.
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Conflicts of interest
There are no conflicts of interest.
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